I’m confused. Someone told me solar is expensive because you don’t just have to buy the panels, but also get an inverter, and then you have to replace it. What’s an inverter, and should I really care?

Solar Sally (maybe)

Dearest Maybe Solar Sally,

All you really need to know about an inverter is that it converts the electricity received into the solar panels into the electricity you receive through your electric outlets.

To be slightly more technical, an inverter changes direct current “DC” energy that solar panels produce into alternating current or “AC” energy that your t.v. and computer uses. In fact, unless you’re out in the middle of nowhere and off the grid, anything you plug is going to require AC energy. So the inverter is necessary for solar.

As to cost, inverters don’t last as long as solar panels. Panels last 25-30 years, some even longer. Inverters generally conk out in 12-15 years. A solar installer should tell you about this. These days, inverters cost around $1200-2000, which is included in your initial solar system price.

However, in 15 years when your inverter goes bust, that price may be significantly lower…or the same. It’s unlikely to be more. So, worst case, be prepared to replace the inverter 10-15 years from now. A good solar company will be showing you this info in the sales proposal and/or presentation. If they don’t ever mention it …. that’s not a good policy, in my opinion. Add that aspect to your selection process.

The good news is that by the time your inverter needs replacing, your system has usually paid for itself. Even better, for the next 10 to 15 years of your solar panel life, the further energy savings should more than offset this expense….by a lot.

An installer might also suggest a new kind of inverter, called “micro inverters.” Instead wiring all the panels together and hooking it up to the big box on the wall, the DC to AC conversion takes in a little box installed with each solar panel. These new inverters are also supposed to last the same amount of time as traditional inverters.

The main advantage to these new micro inverters has to do with keeping more of your solar panels working when a cloud passes or there’s some kind of temporary shading. With micro inverters, only the panel that is shaded will stop producing energy while the cloud passes. With the traditional inverter, the ENTIRE row of solar panels will stop working until the cloud passes. This is because of the way solar panels are typically wired in “parallel.” It also makes the solar panel design more flexible, allowing solar to be more customized to your home.

Bottom line, inverters are needed, they die after 10 years, but your solar savings eventually pay for their replacement.

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